RAPID-DETERMINATION OF TRACE QUANTITIES OF THALLIUM IN HEAT-RESISTING COBALT AND NICKEL-ALLOYS BY GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY

A simple and rapid analytical method has been developed for the direct determination of trace quantities of thallium in nickel and cobalt-base heatresisting alloys by graphite furnace atomic absorption spectrometry. Hydrofluoric acid, sulphuric acid, and hydrogen peroxide were used for the dissolution of a wide variety of these alloys. The interferences of matrix elements and acids were eliminated. The absorbance of thallium is constant over a wide range of ashing temperatures. Synthetic standard solutions composed of nickel or cobalt matrix and thallium were used for calibration. The detection limit for thallium by this method is 0.2 ppm in the sample. Mechanisms of the interferences are discussed. © 1979 Springer-Verlag.